The present invention relates to a portable type information processing terminal device containing an integrated circuit element of a non-contact communication system such as an RFID (Radio Frequency Identification) system.
So-called RFID systems adapted to use a non-contact type IC card are known in the field of automatic check gates of railway stations, security systems for checking persons going into and out of buildings and electronic money systems and the like.
An RFID system typically includes one or more than one non-contact type IC card and a reader/writer for writing data on, and reading data from, the non-contact type IC card. In the RFID system, the antenna coil of the reader/writer and that of the IC card are magnetically coupled to each other by inductive coupling to allow a non-contact data communication to take place between the IC card and the reader/writer.
Data can be exchanged easily and rapidly in such an RFID system because it is no longer necessary to insert an IC card into a reader/writer or contact an IC card to a metal contact as in the case of conventional contact-type IC card systems. Additionally, electric power is supplied to the non-contact type IC card as the AC magnetic field that is excited by the antenna coil of the reader/writer is applied to the IC card. In other words, the IC card is not required to contain a power source such as a battery in the inside and operates highly reliably so that it needs fairly minimal maintenance services. In a known RFID system, a reader/writer is installed in a portable type information processing terminal device such as PDA (Personal Digital Assistants) and the portable type information processing terminal device is adapted to read data from the non-contact type IC card and update the data (see Patent Document 1: Jpn. Pat. Appln. Laid-Open Publication No. 2001-307032).
Meanwhile, a portable type information processing terminal device such as a PDA or a portable type telephone set is designed so as to be constantly carried by the user when the user goes out. Therefore, if a portable type information processing terminal device is provided with the functional feature of a non-contact type IC card, the user of the portable type information processing terminal device who always carries it does not have to carry any other non-contact type IC card to a great advantage on the part of the user.
However, since portable type information processing terminal devices are compact but multifunctional, metal parts are highly densely mounted in a small cabinet thereof. For example, the printed circuit board such a device has an electrically conductive multilayer structure and electronic parts such as integrated circuit elements which are highly densely mounted on the multilayer printed circuit board. Additionally, such a portable type information processing terminal device contains a battery pack as a power source of the device. The battery pack contains a metal as a material of a frame or the like. Therefore, when an antenna coil is arranged in the cabinet of a portable type information processing terminal device, the resonance frequency of the antenna coil can be remarkably modified under the influence of the metal parts mounted in the cabinet to make it difficult to regulate the resonance frequency of the antenna coil and at the same time, to secure the card voltage for driving at least the signal processing integrated circuit element connected to the antenna coil.
Additionally, if the signal processing integrated circuit element of an RFID system is mounted not on the substrate where the antenna coil is arranged but on the main substrate of the portable type information processing terminal device, the antenna coil and the signal processing integrated circuit element are separated from each other by a long distance. As the antenna coil and the signal processing integrated circuit element are separated from each other by a long distance, the resistance between the antenna coil and the signal processing integrated circuit element rises, which results in a large loss. Furthermore, the performance of the device is degraded in terms of anti-external-noise performance.
As pointed out above, it is not possible for a portable type information processing terminal device to reliably transmit and receive data by simply arranging a non-contact type IC card in the device.
Patent Document 2 (Jpn. Pat. Appln. Laid-Open Publication No. 2003-87385) describes a technique that may appear to resemble the present invention. However, the portable type telephone set described in Patent Document 2 is characterized by arranging an RFID tag on an antenna and, thus, is different from a portable type information processing terminal device according to the present invention in which an RFID tag is contained in a cabinet.